Apparatus for the computer assisted setup of a machine tool table

ABSTRACT

An apparatus to assist a machinist in the setup of a remote computer controlled machine tool table has an X-axis electronic gauge block assembly, a Y-axis electronic gauge block assembly, and a Z-axis electronic gauge block assembly each positioned on the machine tool table, to respectively collect X-axis probe position values, Y-axis probe position values, and Z-axis probe position values. Environmental sensors collect environmental values. An electronics processing system establishes a raw X-axis probe position, a raw Y-axis probe position, and a raw Z-axis probe position. A wireless interface transmits the environmental values, the raw X-axis probe position value, the raw Y-axis probe position value, and the raw Z-axis probe position value to the remote computer and receives from the remote computer refined probe position values to assist the machinist in the setup of the machine tool table.

TECHNICAL FIELD

The present invention relates generally to machine tool tables. Moreparticularly, the invention relates to the computer assisted setup of amachine tool table.

BACKGROUND

Software for CAD (computer assisted design) is typically used to designa part, and software for CAM (computer assisted manufacturing) istypically used to make the part. It would be desirable to develop CAS(computer assisted setup) that works together with the CAM process toallow more efficient and more accurate operation of part manufacturing.Ideally, CAS would assist the machinist during setup of the machine tooltable and also during the fabrication process.

A CAD process creates an engineering drawing comprising a 3D digitalrepresentation of a part. For a square prism type part, the 3D digitalrepresentation may contain six views represented by orthographicprojections that describe features to be machined into each of the sixfaces. The CAM process provides all the details necessary for the CNC(computer numeric control) mill to machine this part starting from asolid blank material, called the work piece. The CAM process also givesinstructions whereby the machinist may have to place and replace thiswork piece six or more times. Drawing origin coordinates Xdi, Ydi, andZdi may be defined; in the case of a square prism i may range from 1 to6, for each of the six faces of the work piece that is held in a visecomprising a fixed jaw and a clamping jaw.

Each placing step may require a new origin located in Xdi, Ydi, and Zdicoordinates referenced to a reference point on the fixed vise jaw. Andeach placing step will require an indexed stop to determine the Xdicoordinate, parallels to determine the Zdi coordinate, and manipulationof the work piece. That is, the work piece is clamped using the viceclamping jaw. This involves pushing the work piece up against the fixedvise jaw to determine the Ydi coordinate and pushing the work piece upagainst the indexed stop to determine the Xdi coordinate. Typically themachinist assumes that the work piece remains upon and against theparallels during the clamping process to determine the Zdi coordinate.

The failure of the work piece to be properly positioned during theclamping process is referred to as a seating failure. Seating failuremay also result from debris, created during the work piece cuttingoperations, adhering to a reference surface located on the fixed visejaw, the indexed stop or the parallels. It would be desirable to have aCAS process to assist the machinist during work piece manipulation toidentify seating failure. The prompt identification of seating failureallows the machinist to remedy the problem before continued cuttingoperations may ruin the work piece.

It is desirable to have a CAS process for each placing step, where themachinist may have to setup a stop or place parallels, for the computerto assist the machinist by providing instructions as to the exactcoordinates so as to insure the placing step is performed accurately andcorrectly. Since these exact coordinates may differ from the typicaldigital readout values, a new display located on the machine tool tablewould make it much easier for the machinist to have access to thisinformation during setup of the machine tool table. Measurement probes,such as edge finder tools, may be used to determine the exact coordinatepositions of vices, indexed stops, parallels and features on the workpiece. The performance of these tools is also improved by using the newdisplay of refined positions.

Typically, a machinist uses a flexible touch probe with a dial indicatorto measure small deviations between a gauge block and features on themachined part with an accuracy of ±0.0001 inches. This inspectionprocess, sometimes using a machine referred to as a CMM (coordinatemeasurement machine), is performed after the part has been made, and istypically carried out in a clean room environment.

It is desirable to have a CAS process with this capability on themachine tool table so that the ±0.0001 inch accuracy can be referred toboth before and during part fabrication. As a flexible touch probe witha dial indicator would be gummed up by the CNC machine cutting andcoolant fluids, a new approach is needed that establishes a coordinatesystem of accurate points. U.S. Pat. No. 9,235,206 discloses a rigidprobe to determine a single accurate position called an origin. It wouldbe desirable to extend this approach to determine a coordinate system ofaccurate points.

With a rigid probe in the tool holder and the exact coordinates toinsure each step is performed accurately and correctly, it would bebeneficial to have a CAS process that uses the probe to assist themachinist in the setup of indexed stops. It is also desirable to have anindexed stop with probe engagement features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top view of a milling machine.

FIG. 1B is a side view of a milling machine.

FIG. 2A is a side view of a probe.

FIG. 2B is a top view of X, Y, and Z axis electronic gauge blockassemblies installed on a milling machine table.

FIG. 3A is a side view of a Z axis electronic gauge block mounted on abar.

FIG. 3B is a top view of a Z axis electronic gauge block mounted on abar.

FIG. 4A is a side view of Z axis moveable probe engagement components.

FIG. 4B is a side view of Y axis moveable probe engagement components.

FIG. 4C is a side view of X axis moveable probe engagement components.

FIG. 5A is a side view of the inside of an electronic gauge block.

FIG. 5B is a top view of the inside of an electronic gauge block.

FIG. 6 shows electrical circuit elements of an electronic gauge block.

FIG. 7A shows a CNC program.

FIG. 7B shows milling machine control electronics.

FIG. 8 is a side view of an electronic gauge block Z reference positioncalibration apparatus.

FIG. 9 is a top view of an electronic gauge block X reference positioncalibration apparatus.

FIG. 10 is a side view of a Z axis coordinate system.

FIG. 11 is a top view of an X axis coordinate system.

FIG. 12A is a side view of a probe engaging indexed stop.

FIG. 12B is a top view of a probe engaging indexed stop.

FIG. 13A is a top view of the Y and Z axis probe engagement for theprobe engaging indexed stop.

FIG. 13B is a top view of the X axis probe engagement for the probeengaging indexed stop.

Like reference numerals refer to corresponding parts throughout theseveral views of the drawings.

SUMMARY

An apparatus to assist a machinist in the setup of a remote computercontrolled machine tool table has an X-axis electronic gauge blockassembly, a Y-axis electronic gauge block assembly, and a Z-axiselectronic gauge block assembly each positioned on the machine tooltable, to respectively collect X-axis probe position values, Y-axisprobe position values, and Z-axis probe position values. Environmentalsensors collect environmental values. An electronics processing systemestablishes a raw X-axis probe position, a raw Y-axis probe position,and a raw Z-axis probe position. A wireless interface transmits theenvironmental values, the raw X-axis probe position value, the rawY-axis probe position value, and the raw Z-axis probe position value tothe remote computer and receives from the remote computer refined probeposition values to assist the machinist in the setup of the machine tooltable.

DETAILED DESCRIPTION

An apparatus is described herein, which uses X-axis, Y-axis, and Z-axiselectronic gauge block assemblies for the computer assisted setup of amachine tool table including the determination of a refined positioncoordinate system. These refined positions improve the raw digitalreadout values by taking into account how environmental factors such astemperature, relative humidity, and plumb bob indications affect themachine tool table. The apparatus may display these refined positionswith a display located on the machine tool table and assist themachinist in setting up a vise and stops on the machine tool table andalso in the manipulation of the work piece during manufacture.

FIG. 1A is a top view of the relevant elements of a typical three-axisvertical CNC milling machine, with a tool holder 110, which is used tohold rotary cutter 112. The tool holder 110 is used to change tools andstore tools in the CNC milling machine. The table 101 moves in the X andY axis directions and the tool holder 110 moves in the Z axis direction.

A tool pre-setter 140 is shown on the table 101. It serves to measureeach rotary cutter 112 to determine the cutting diameter and the Z axisoffset from the bottom of rotary cutter 112 to the tool holder 110 Zaxis reference surface.

Indexed stops 104 and 114 for left handed origins and indexed stops 105and 115 for right handed origins are shown, where typically only oneneed be used at a time to define the X axis location of a particularorigin for work piece 100. Indexed stops 104, 114, 105, and 115 areindexed to the fixed vise jaw 102 so that it is convenient to remove andreplace such indexed stops in their original position and orientationduring the fabrication process. Indexed stops 104 and 105 are internalto the vise and are attached to the fixed vise jaw 102. Indexed stops114 and 115 are external to the vise and are mounted on the table 101.

In one embodiment indexed stop 114 is a probe engaging indexed stop. Thedescription of a probe engaging indexed stop 114 is described below inconnection with FIG. 12A and FIG. 12B. The probe 203 as described belowin connection with FIG. 2A, is used to engage the probe engaging indexedstop 114 to set it up as described below in connection with FIG. 13A andFIG. 13B. The probe engaging indexed stop 114 is mounted on the tableand may serve as either a right handed or left handed stop. In addition,probe engaging stop 114 may serve as an external or internal stoprelative to the vise. As discussed below, when used as an internal stop,the probe engagement may be set up with a probe 203 that is external tothe vise that may feature a miniature bar for small and hard to reachwork pieces 100.

Fixed vise jaw 102 has a reference point 119 with coordinates Xv, Yv,and Zv, where Xv and Yv are defined by reference surfaces on fixed visejaw 102, and Zv is defined by the top surface of table 101 in thevicinity of the reference point 119. Parallels 106 are also shown insidethe vise and are used to define a fixed offset from the Zv position ofthe bottom of the work piece 100.

Hence the X and Y coordinates of origins 107, 117, 108, and 118 aredetermined with respect to reference point 119 on the fixed vise jaw102. The Z coordinates of all origins 107, 117, 108, and 118, aredetermined with respect to the table top 101 in the vicinity of eachstop.

Also shown in FIG. 1A is plumb bob sensor 130, typically required tolevel the table 101 during installation. The plumb bob sensor 130 isusually removed during CNC milling machine operation and is notreferenced during setup.

FIG. 1B is a side view of table 101 and tool holder 110 and rotarycutter 112 of the CNC milling machine. A digital readout 120 on the CNCmilling machine displays the coordinates in each of the X, Y, and Zaxes. The invention provides improved digital readout 120 values, whichare called herein refined positions. The refined positions define acoordinate system with a reference point with values Xr and Yr and Zr,where this process is described below in connection with FIGS. 10 and11. When the vise reference point 119 with values Xv and Yv and Zv, andthe X and Y coordinates of origin 117 are determined using refinedpositions, it is possible to achieve ±0.0001 inch accuracy in the setupof the vise and the probe engaging indexed stop 114.

FIG. 2A is a side view of probe 203 mounted in the tool holder 210. Toachieve high accuracy, tool holder 210 is a shrink fit tool holder suchas made by Techniks, Inc. in Indianapolis, Ind. with part number 29021referred to as CAT40×⅜″ ID with a TIR (total indicated runout) of 0.0001inch.

FIG. 2B is a top view of the table 101 showing the vice with fixed jaw102, fixed vise jaw reference point 119, clamping jaw 103, parallels106, and indexed stops 104, 114, 105 and 115. The plumb bob sensor 130and tool setter 140 are not shown, but may be present. When tool setter140 is present, it is typically enclosed so as to avoid contaminationduring part manufacture.

During setup, fixed jaw 102 is positioned on the table 101, such thatthe orientation of the edge containing fixed vise jaw reference point119 is in the X axis direction. The machinist typically uses a flexibleprobe with a dial indicator to insure that the runout in the Y axisdirection of the Y axis point is less than ±0.0001 inches as measuredbetween fixed vise jaw reference point 119 and the point on fixed jaw102 farthest from point 119. This orientation of the edge containingfixed vise jaw reference point 119 is in the X axis direction and nowdefines the X axis and this Y axis point defines Yv.

The electronic gauge block Y assembly 260 includes electronic gaugeblock 301, bar 201, and electronic cable 361. The setup of the bar 201is similar to the setup of the fixed vise jaw 102. During setup the bar201 is first positioned in the X axis direction with a flexible probewith a dial indicator to insure the Y axis runout is less than ±0.0001inch, similar to the process for vise fixed jaw 102. Electronic gaugeblock 301 provides a signal over electronic cable 361 to electronicsinterface box 224 to determine a raw Y reference position, Yr.

Electronic gauge block X assembly 270 includes electronic gauge block302, bar 202, and electronic cable 362. The bar 202 is aligned in the Yaxis direction, with a flexible probe with a dial indicator to insurethe X axis runout is less than ±0.0001 inch. More details for the setupof the bar 202 are provided below in connection with the description ofFIG. 9. The bar 202 holds the electronic gauge block 302 and electroniccable 362. Electronic gauge block 302 provides a signal over electroniccable 362 to electronics interface box 224 to determine a raw Xreference position Xr.

Electronic gauge block Z assembly 250 includes electronic gauge block300, bar 200, and electronic cable 360. The bar 200 is aligned in the Zaxis direction. More details for the setup of bar 200 are provided belowin connection with the description of FIG. 8. Electronic gauge block 300provides a signal over electronic cable 360 to electronics interface box224 to determine a raw Z reference position Zr.

The three electronic gauge blocks assemblies 250, 260, and 270, alongwith electronics interface box 224, enable the computer assisted setup,or CAS, operation of the CNC milling machine to determine the refinedpositions to within ±0.0001 inch accuracy, and hence the required originpositions for each placing step in the CAM process for part manufacture.For example, knowing the reference position Xr, Yr, and Zr, allows therequired origin positions 107, 117, 108, or 118 to be determined by arefined position fixed offset first to the vise jaw reference point 119,at coordinates Xv, Yv, Zv, and then by a refined position fixed offsetto either required origin position 107, 117, 108, or 118.

FIG. 3A shows a side view and FIG. 3B shows a top view of the Z axiselectronic gauge block assembly 250 with electronic gauge block 300mounted on bar 200. Reference surface 235 establishes the X axisposition, and reference surface 230 establishes the Y axis position ofelectronic gauge block 300 on the bar 200. Reference surfaces 245 and240 are convenient surfaces for flexible touch probe indicator points onbar 200 to insure bar 200 has zero runout error in the Z axis direction,and hence the electronic gauge block tip 310 is pointing in the Z axisdirection. Reference surface 240 also defines the position of Zr forplacing gauge blocks as described below in connection with FIG. 10 toestablish the Z axis of the refined position coordinate system.

FIG. 3B also shows holes 222 on bar 200 used for push-pull alignmentscrews described below in connection with FIG. 8. Holes 220 on bar 200allow calibration plate 800 to be secured to bar 200 as described belowin connection with FIG. 8. The flexible seal 330 prevents contaminationfrom entering the block 300. The flexible seal 330 adheres to tip 310and block 300, and also allows tip 310 to move freely in the Z axisdirection.

The tip 310 can move about plus or minus 0.0500 inches in the Z axisdirection above and below the reference position Zr defined by referencesurface 240. The moveable probe engagement components of electronicgauge block 300 are shown in FIG. 4A where the tip 310 engages the probe203. FIG. 4A shows a side view of the moveable probe engagementcomponents where the bottom side of probe 203 engages the tip 310 at thereference position Zr.

The moveable probe engagement components of electronic gauge block 301are shown in FIG. 4B where the tip 311 engages the cylinder side ofprobe 203 at the reference position Yr. The moveable probe engagementcomponents of electronic gauge block 302 are shown in FIG. 4C where thetip 312 engages the cylinder side of probe 203 at the reference positionXr.

FIG. 5A shows a side view of the inside of the electronic gauge block300. The tip 310 is connected to the first end of a shaft 510 and aspring 550 is connected to the second end of shaft 510. The shaft 510motion is constrained by bearings 520 and 530. A shutter 540 isconnected to the shaft and is used by optical sensor 560. Bearings 520,530, spring 550, and optical sensor 560 are held in place by block 300.Also shown in FIG. 5A is an electrical cable 360 entering block 300 andconnecting to optical sensor 560.

FIG. 5B shows a top view of the inside of electronic gauge block 300.Electrical cable 360 connects to optical sensor 560 by splitting intofour wires connecting the LED 570, the reference photo detector 580, thesignal photo detector 590, and a ground wire (not shown). The light rays575 strike the reference photo detector 590, and the shutter 540 blocksa portion of light rays 575 reaching the signal photo detector 590.

Electronic gauge blocks 301 and 302 have configurations corresponding tothose described in connection with electronic gauge block 300.

The components inside of electrical interface box 224 are shown in FIG.6. A rechargeable battery 600 powers the DC power supply 620, as well asthe electronics in the interface box 224. A multiplexer 610 accepts thethree cables 360, 361, and 362, and as shown in this case selects cable360. The DC power supply 620 powers the LED 570. The pre amp 630converts the reference photo detector 580 current into voltage, and thepre amp 640 converts the signal photo detector 590 current into voltage.The ground is not shown. The divider 650 takes the ratio of the signalvoltage to the reference voltage to normalize the signal voltage. Thesubtract element 660 removes a Z axis offset 670 voltage from thenormalized signal voltage. Finally the comparator 680 goes low when thenormalized signal voltage from the subtract element 660 crosses zero andbecomes negative, thereby determining the reference position for Zr.

Wireless remote control 690 receives a signal from a remote computer 700shown in FIG. 7, and sets the multiplexer 610 to select cable 360, andsets the Z axis offset voltage on offset 670. The state of comparator680 is sent back to the remote computer 700 using the wireless remotecontrol 690. A key control processor 695 accepts a key control code viathe wireless remote control 690 from the remote computer 700. If thereceived key control code matches a stored key control code, access tothe system is enabled.

Wireless remote control 690 receives refined position values from theremote computer 700 wireless remote control 701. A display controlprocessor 693 in electrical interface box 224, may control the displayof refined positions on displays external to electrical interface box224 as described below in connection with the description of FIGS. 10and 11.

Environmental sensors, such as temperature sensor 685, humidity sensor686, and plumb bob sensor 687 collect analog voltages that are convertedto digital signals by ADC 688 and are sent to the remote computer 700using the wireless remote control 690.

When wireless remote control 690 selects cable 361 and provides a Y axisoffset 670 voltage, the state of comparator 680 is monitored for atransition to a low state, thereby determining the reference positionfor Yr. This information is sent to the remote computer 700.

When wireless remote control 690 selects cable 362 and provides an Xaxis offset 670 voltage, the state of comparator 680 is monitored for atransition to a low state, thereby determining the reference positionfor Xr. This information is sent to the remote computer 700.

FIG. 7A gives an example of a CNC program for a CNC milling machine(e.g., a Haas Mill 96-8000). FIG. 7B illustrates a computer 700operating in conjunction with a CNC milling machine 750. In oneembodiment, the remote computer 700 loads the CNC program into thememory of the CNC milling machine 750 over RS-232 cable 710. When theCNC milling machine is run with this example program, the Z axisposition of tool holder 210 with probe 203 is moved down step by stepuntil the Z axis electronic gauge block tip 310 reaches the reference Zposition Zr. The state of comparator 680 is monitored for a transitionto a low state by remote computer 700. The remote computer 700 providesthis digital I/O control signal to the CNC milling machine by usingcable 720, where the specific digital I/O terminal is labeled Q15 in theprogram.

The name of the numeric program is STEP AND CONDITIONAL BRANCH TEST. Thestart and end of the program are indicated with “%” signs. The programuses the following G and M codes: G103 P1 instructs the numeric millprogram to look ahead one line at a time.

G04 P1.0 instructs the numeric mill program to dwell for 1.0 second atthis line of code for the milling machine to settle, typically after amove step.

G00 Z-10.0000 instructs the numeric mill program to move the Z axis toolholder to move to position Z=−10.0000, where in this example the toolholder 210 holds the probe 203.

M96 P4 Q15 instructs the numeric mill program to check the digital I/Oterminal labeled Q15 and proceed to the next line of code if the stateis high and proceed to line N4 if the state is low.

DPRNT instructs the numeric mill program to send the message “Step 1Z=−10.0000 (the current position of the Z axis in CNC mill memorylocation #5023) Flag IS HI” back over the RS-232 cable 710 to remotecomputer 700.

The remote computer 700 also has a wireless remote control 701 thatprovides communication to wireless remote control 690. Remote computer700 has a relational database 740 of data from environmental sensors,such as temperature sensor 685, humidity sensor 686, and plumb bobsensor 687. The remote computer 700 uses relational database 740 to makecorrections to X, Y, and Z raw positions. The corrections result inrefined positions of the coordinate system. The refined positions allowmore accurate control of the milling machine. Access to the relationaldatabase may be controlled with a password or key, such as the keyassociated with access to the wireless remote control 690.

The remote computer 700 uses the formula in Equation 1 below to computethe refined positions Z from the raw Z axis values γ. The remotecomputer700 searches relational database 740 to obtain the proper Az andBz and Cz coefficients used in Equation 1 below as related to thepresent readings of environmental sensors 685 and 686 and 687.

The remote computer 700 uses the formula in Equation 5 below to computethe refined positions X from the raw X axis values α. The remotecomputer700 searches relational database 740 to obtain the proper Ax andBx and Cx coefficients used in Equation 5 below as related to thepresent readings of environmental sensors 685 and 686 and 687. In asimilar manner, remote computer 700 computes the refined Y axis valuesfrom raw Y axis values.

Remote computer 700 uses temperature sensor 685 to monitor temperatureat regular intervals, of for example 1 minute, and notify the operatorif the temperature changes more than a preset limit, of for example ±1°F., thereby indicating that the milling machine is not in thermalequilibrium.

Remote computer 700 uses plumb bob sensor 687 to monitor table tilt atregular intervals, of for example 1 hour, and notify the operator if thetable tilts more than a preset limit, of for example ±0.5 degrees,thereby indicating an error condition that the milling machine has beenphysically disturbed.

FIG. 8 shows a side view of the Zr axis calibration procedure forelectronic gauge block Z assembly 250. Dual base element 810 secures thebar 200 to the top of table 101 using a flexure 815. The dual baseelement 850 has push-pull screws 860 and 861 that both position and lockbar 200 so that reference surfaces 245 and 240 have less than ±0.0001inch runout in the Z axis direction as measured by a flexible touchprobe with a dial indicator as described previously in connection withthe description of FIGS. 3A and 3B.

When calibration plate 800 is fastened to bar 200 using clamping screws801 and 802, the tip 310 is depressed to make the position even with thereference surface 240. While the calibration plate 800 is still clampedthe computer 700 selects cable 360 and adjusts the Z axis offset 670 sothat comparator 680 will transition from a high to low state. Electronicgauge block 300 reference position Zr is now calibrated by the Z axisoffset 670 value for Zr stored in computer 700.

FIG. 9 shows a side view of the Xr axis calibration procedure forelectronic gauge block X assembly 250. Dual base element 910 secures thebar 201 to the top of table 101 using a flexure 915. The other dual baseelement 950 has push-pull screws 960 and 961 that both position and lockbar 201 so that reference surfaces 970 and 980 have less than ±0.0001inch runout as measured by a flexible touch probe with a dial indicator.

When calibration plate 800 is fastened to bar 201 using clamping screws801 and 802, the tip 312 is depressed to make the position even with thereference surface 980. While the calibration plate 800 is still clampedthe computer 700 selects cable 362 and adjusts the X axis offset 670 sothat comparator 680 will transition from a high to low state. Electronicgauge block 302 reference position Xr is now calibrated by the X axisoffset 670 value for Xr stored in computer 700. Similarly, theelectronic gauge block 301 reference position Yr is also calibrated bythe Y axis offset 670 value for Yr stored in computer 700.

FIG. 10 shows elements for setting up a Z axis coordinate system usingelectronic gauge block Z assembly 250. Electrical interface box 224receives refined position values from remote computer 700 and maydisplay these refined Z axis positions on a display located on interfacebox 224 as shown in the FIG. 10. Gauge block 1000 is placed on referencesurface 240. A flexible touch probe touches surface 240 and the digitalreadout 120 Z value is recorded. This corresponds to the referenceposition Zr. The point 1001 on the top of gauge block 1000 is nowtouched with the flexible touch probe and the value of the digitalreadout 120 Z value is recorded. This Z value corresponds to the raw γ₁axis position.

The values of temperature from temperature sensor 685, humidity fromsensor 686, and plumb bob sensor 687 are recorded. The refined Z1 axisposition depends on the length of the gauge block 1000 at thetemperature sensor 685 value. The data values (Z1, γ₁) are used inEquation 2 shown below.

This process is continued with gauge block 1010 placed on top of gaugeblock 1000. The touch probe is used to record the raw value of thedigital readout 120 for the point 1011. This position is the raw γ2position. The refined Z2 position is the sum of gauge block 1000 lengthplus gauge block 1010 length at the temperature sensor 685 value. Thedata values (Z2, γ₂) are used in Equation 3 shown below.

Using gauge block 1020 another set of values for the raw digital readout120 indication Z value of γ3 position of point 1021, and the refinedposition of Z3 defined by the sum of the temperature corrected lengthsof gauge blocks 1000, 1010, and 1020. The data values (Z3, γ₃) are usedin Equation 4 shown below.

The value of the refined value of Z for any point γ on the intervalbetween Zm and Z3 can be calculated from the relation:Z=A _(z) γ+B _(z)γ² +C _(z)γ³  Equation 1.where Z is the refined position, and γ is the raw position.

Az, Bz, and Cz are three coefficients determined from the data above bythe three equations:Z1=A _(z)γ₁ +B _(z)γ₁ ² +C _(z)γ₁ ³  Equation 2.Z2=A _(z)γ₂ +B _(z)γ₂ ² +C _(z)γ₂ ³  Equation 3.Z3=A _(z)γ₃ +B _(z)γ₃ ² +C _(z)γ₃ ³  Equation 4.Let S1=Z1γ₂ −Z2γ₁S2=γ₂γ₁ ³−γ₁γ₂ ³S3=γ₂γ₁ ²−γ₁γ₂ ²S4=Z1γ₃ −Z3γ₁S5=γ₃γ₁ ³−γ₁γ₃ ³and S6=γ₃γ₁ ²−γ₁γ₃ ²then Cz=[S3 S4−S6 S1]÷[S3 S5−S2 S6]and Bz=[S1−Cz S2]÷S3and Az=S1÷γ₁ −Bzγ ₁ −Czγ ₁ ²This set of Az, Bz, and Cz values for the environmental sensor 685, 686,and 687 readings are stored in the relational database 740. Additionalsets of Az, Bz, and Cz values are determined for temperature, humidity,and plumb bob values that span the operational environmental limits ofthe milling machine and are stored in the relational database 740.

FIG. 11 shows elements for setting up an X axis coordinate system usingelectronic gauge block X assembly 270. Electrical interface box 224receives refined position values from remote computer 700 and maydisplay these refined X and Y axis positions on a display located oninterface box 224 as shown in the FIG. 11. Gauge block 1100 is placed onreference surface 980. A touch probe touches surface 980 and the digitalreadout 120 X value is recorded. This corresponds to reference positionXr. The point 1101 at the end of gauge block 1100 is now touched withthe touch probe and the value of the digital readout 120 X value isrecorded. This X value corresponds to the raw α₁ axis position, and soon for α₂ and α₃. The data set (X1, α₁) is used in Equation 6. The dataset (X2, α₂) is used in Equation 7. And the dataset (X3, α₃) is used inEquation 8.

The value of the refined value of X for any point α on the intervalbetween Xm and X3 can be calculated from the relation:X=A _(x) α+B _(x)α² +C _(x)α³  Equation 5.where X is the refined position, and α is the raw position.

Ax, Bx, and Cx are three coefficients determined from the data above bythe three equations:X1=A _(x)α₁ +B _(x)α₁ ² +C _(x)α₁ ³  Equation 6.X2=A _(x)α₂ +B _(x)α₂ ² +C _(x)α₂ ³  Equation 7.X3=A _(x)α₃ +B _(x)α₃ ² +C _(x)α₃ ³  Equation 8.Let Q1=X1α₂ −X2α₁Q2=α₂α₁ ³−α₁α₂ ³Q3=α₂α₁ ²−α₁α₂ ²Q4=X1α₃ −X3α₁Q5=α₃α₁ ³−α₁α₃ ³and Q6=α₃α₁ ²−α₁α₃ ²then Cx=[Q3 Q4−Q6 Q1]÷[Q3 Q5−Q2 Q6]and Bx=[Q1−Cx Q2]÷Q3and Ax=X1÷α₁ −Bxα ₁ −Cxα ₁ ²

This set of Ax, Bx, and Cx values for the environmental sensor 685, 686,and 687 readings are stored in the relational database 740. Additionalsets of Ax, Bx, and Cx values are determined for temperature, humidity,and plumb bob values that span the operational limits of the millingmachine and are stored in the relational database 740.

Setting up a Y-axis coordinate system uses an electronic gauge blockassembly 270. Y-axis processing is performed in a similar manner toX-axis processing. This completes the CAS process of determining arefined position X-axis, Y-axis and Z axis coordinate system that spansthe space above the machine tool table defined by the values Xr to X3,Yr to Y3, and Zr to Z3.

FIG. 12A shows a side view and FIG. 12B shows a top view of a preferredembodiment of a probe engaging indexed stop 114. Base 900 is mounted ontable 101, and contains a slot aligned substantially in the Y axisdirection. Post 910 slides in the Y axis direction into the slot of base900. Clamp 901 may secure the post 910 using locking screws 902. Slider920 slides substantially in the Z axis direction on post 910 and issecured in position by locking screw 921. Bar 930 slides substantiallyin the X axis direction on slider 920, and is secured in position bylocking screw 922.

The position of point 931 on bar 930 determines the stop position forleft handed origin 117 as previously described in FIG. 1A. The positionof point 932 on bar 930 may be used to determine the stop position forright handed origins such as 108 or 118 as previously described in FIG.1A.

FIG. 13A shows how the probe 203 cylinder side may engage post 910 atpoint 911 to set the Y axis position of the post 910. The bottom side ofprobe 203 may engage the slider 920 to set the Z axis height of slider920.

FIG. 13B shows how the probe 203 cylinder side engages the bar 930 todetermine the X axis position of point 931 on bar 930 for an externalprobe engaging indexed stop 114. The computer 700 controls the positionof the probe 203 in accordance with refined position information inrelational data base 740 values, in this case for a left handed originsuch as origin 117. Similarly, the probe 203 cylinder side may engagethe bar 930 at point 932 to determine the X axis position of point 932for an external probe engaging indexed stop 115 useful for setting aright handed origin such as origin 118.

FIG. 13B also shows how the probe 203 cylinder side engages the bar 930in this case at point 932 to determine the X axis position of point 931on bar 930 for an internal probe engaging indexed stop 104. The computer700 controls the position of the probe 203 in accordance with refinedposition information in relational data base 740 values, in this casefor a left handed origin such as origin 107. Similarly, the probe 203cylinder side may engage the bar 930 at point 931 to determine the Xaxis position of point 932 for an internal probe engaging indexed stop105 useful for setting a right handed origin such as origin 108.

The CNC milling machine may be controlled directly by the machinist, andthe probe in the tool holder replaced with a measuring probe such as anedge finder. In an alternative embodiment the reference surfaces on bars200, 201, and 202 may be measured to determine the raw X axis, Y axis,and Z axis probe raw reference positions. The measuring probe is movedby the machinist to the raw reference positions on bars 200, 201, and202 and the machinist stores this data in the CNC milling machine 750memory. The computer 700 may access the CNC milling machine 750 memoryto read the raw reference positions, and then follow the process aboveto determine the coefficients to add to the relational database 740 tospecify the actual refined reference positions as related to theenvironmental values. The computer 700 obtains the environmental valuesusing the electrical processing in electrical interface box 224.

This CAS process may be continued as above using the gauge blocks tospecify refined reference points defining the entire coordinate systemand using computer 700 to store the values in the relational database740 along with the environmental values that span the operational limitsof the milling machine which are also stored in the relational database740.

In another manual quality control CAS process, a measuring probe such asan edge finder is loaded into the tool holder. The measuring probe ismoved to an X axis probe raw fiducial position on the work piece and themachinist stores this data point in the CNC milling machine 750 memory.

The raw fiducial position may be the X axis coordinate of the X axisedge of the work piece for example. The computer 700 may access the CNCmilling machine 750 memory to read the X axis raw fiducial value andalso use the relational database 740 to specify the actual refined Xaxis fiducial position as related to the environmental values.

The computer 700 also is running the CAM process program and can accessthe required refined X axis fiducial position for this CAM process step.Hence the computer 700 can determine if the actual refined X axisfiducial position is within the accuracy tolerance of the requiredrefined X axis fiducial position.

This process can be repeated for Y axis and Z axis required fiducialpositions on the work piece during each step of the CAM process toprovide an indication of the quality of the work piece duringmanufacture. In the event the accuracy tolerance is out of specificationthe machinist may be notified and possible corrective action takenbefore the part is ruined.

A particular case is when the machinist places the work piece in thevise, and the work piece does not seat properly. Seating problems occurtypically when the clamping jaw of the vise forces the part out of itsproper position, and also when any of the reference surfaces of thevise, parallels, and stops contain debris from the cutting material thatis not properly cleaned away from the reference surfaces. When a seatingproblem is determined and the machinist notified prior to furthercutting operations, the work piece may be properly seated and therebysaved from ruin.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the invention.However, it will be apparent to one skilled in the art that specificdetails are not required in order to practice the invention. Thus, theforegoing descriptions of specific embodiments of the invention arepresented for purposes of illustration and description. They are notintended to be exhaustive or to limit the invention to the precise formsdisclosed; obviously, many modifications and variations are possible inview of the above teachings. The embodiments were chosen and describedin order to best explain the principles of the invention and itspractical applications, they thereby enable others skilled in the art tobest utilize the invention and various embodiments with variousmodifications as are suited to the particular use contemplated. It isintended that the following claims and their equivalents define thescope of the invention.

What is claimed is:
 1. An apparatus to assist a machinist in the setupof a remote computer controlled machine tool table, comprising; anX-axis electronic gauge block assembly positioned on the machine tooltable, a Y-axis electronic gauge block assembly positioned on themachine tool table, and a Z-axis electronic gauge block assemblypositioned on the machine tool table, to respectively collect X-axisprobe position values, Y-axis probe position values, and Z-axis probeposition values; environmental sensors to collect environmental values;an electronics processing system to establish a raw X-axis probeposition, a raw Y-axis probe position, and a raw Z-axis probe positionderived from an X-axis offset value, the X-axis probe position values, aY-axis offset value, the Y-axis probe position values, and a Z-axisoffset value, and the Z-axis probe position values; and a wirelessinterface to transmit the environmental values, the raw X-axis probeposition value, the raw Y-axis probe position value, and the raw Z-axisprobe position value to the remote computer and to receive from theremote computer refined probe position values to assist the machinist inthe setup of the machine tool table.
 2. The apparatus of claim 1 whereinthe wireless interface receives the X-axis offset value, the Y-axisoffset value and the Z-axis offset value.
 3. The apparatus of claim 1wherein the environmental sensors include a temperature sensor, ahumidity sensor and a planar position sensor.
 4. The apparatus of claim1 further comprising a probe in the form of a rigid gauge pin in ashrink fit machine tool holder.
 5. The apparatus of claim 1 wherein: theX-axis electronic gauge block assembly comprises a first dual baseconfigured for positioning on the machine tool table, with a first barattached to the first dual base by a flexure and a push pull screwarrangement; the Y-axis electronic gauge block assembly comprises asecond dual base configured for positioning on the machine tool table,with a second bar attached to the second dual base by a flexure and apush pull screw arrangement; and the Z-axis electronic gauge blockassembly comprises a third dual base configured for positioning on themachine tool table, with a third bar attached to the third dual base bya flexure and a push pull screw arrangement.
 6. The apparatus of claim 5with an X-axis electronic gauge block attached to the first bar, aY-axis electronic gauge block attached to the second bar, and a Z-axiselectronic gauge block attached to the third bar, wherein the first bar,the second bar and the third bar each have reference surfaces to locategauge blocks.
 7. The apparatus of claim 6 wherein each of the X-axiselectronic gauge block, Y-axis electronic gauge block and Z-axiselectronic gauge block comprises: a tip, a block, wherein the tip isconstrained to move in a single axis direction and the tip is sealed tothe block with a flexible seal, and a sensor positioned within the blockto sense the single axis position of the tip.
 8. The apparatus of claim1 in combination with the computer storing a relational database ofcoefficient values that specify a coordinate system of refined X-axisprobe positions, refined Y-axis probe positions and refined Z-axis probepositions related to the environmental values.
 9. The apparatus of claim1 wherein the computer wirelessly transmits offset values andmultiplexer channel selection controls to the wireless interface. 10.The apparatus of claim 8 in combination with a computer numericcontrolled milling machine, the computer conveying a refined X-axisprobe position, a refined Y-axis probe position and a refined Z-axisprobe position to the computer numeric controlled milling machine. 11.The apparatus of claim 10 wherein the computer numeric controlledmilling machine automatically moves a probe to the refined X-axis probeposition, the refined Y-axis probe position and the refined Z-axis probeposition.
 12. The apparatus of claim 8 wherein the computer generates analert in response to a temperature change exceeding a predeterminedthreshold.
 13. The apparatus of claim 8 wherein the computer generatesan alert in response to changing planar position values exceeding atleast one predetermined threshold.
 14. The apparatus of claim 1 incombination with a probe engaging indexed stop comprising: a baseconfigured for mounting on the machine tool table, the base defining aslot in the Y-axis direction to receive a post, a slider positioned onthe post, the slider being movable along the post in the Z-axisdirection, a bar positioned on the slider, the bar being movable alongthe slider in the X-axis direction, the post the slider and the barconfigured to engage a probe, such that when the post and the slider andthe bar are clamped the bar defines the X-axis of an origin.
 15. Theapparatus of claim 1 further comprising a key control processor tocontrol access to the wireless interface.
 16. The apparatus of claim 8wherein access to the relational database is controlled by a password orkey.
 17. The apparatus of claim 1 further comprising a display controlprocessor to control display of the refined probe position values.